Thoughts on the current slate:
stays in B-.
I know its a got a unique typing for a defogger, as well as having a decent typing defensivley, but it just ends up getting naturally hammered by all the stuff it wants to check. Fairy check. Altaria and Equake, Diancie has Epower, Gardevoir has Focus Blast and Azumarill has superpower. Not to mention it gets worn down really easily due to a lack of reliable recovery. It is also hammered into the ground by 3 of the 4 S rank mons. Being an excellent check to the Latios and Latias, as well as being a pretty unique defogger saves it from dropping into the C ranks, but I can't see it being ranked with Serperior and Omaster.
up to A-
Custap berry was a excellent buff for Skarmory, turning an already relatively decent pokemon into an excellent hazard setter on offensive and hazard stacking teams. Not only does it offer excellent hazard stacking potential, but the ability to smash Diancie and Keldeo through the use of Iron Head and brave bird respectively. On top of this, it has access to some excellent support moves, such as taunt and more importantly, tailwind (which I've been using recently to turn powerful wall breakers into fast sweepers with amazing power). Its other sets are still at large, counter skarmory being one of the most reliable answers to the dreaded mega metagross. I personally feel its more on the level of some of the weaker A- mons then the stronger B+ mons.
up to B-
Seriously one of the most underrated mega's right. First of all, its not completely outclassed by mega gallade. While Gallade has access to knock off, better speed, a more efficient method of boosting, and more usable bulk, it lacks the raw power of Mega Medicham, and the difference is certainly noticeable before a boost. Unlike Gallade, Medicham can pose to be a much more threat to bulky mons that can survive more then two hits from gallade and retaliate with recovery. Dual priority is also a big boon over gallade, giving medicham ways to constantly wear down its checks and "Counters" (though sableye's mega form and mega slower is the only true counters I imagine). Balance teams will often find themselves over whelmed by its sheer power, and this will often cause something to either take immense damage or flat out die on a switch. Certainly better then most of C mons.
up to A+
Now here are a nomination of my own
View attachment 38835 Starmie to A+
Starmie is an incredibly effective pokemon in the current metagame. It hits an incredible speed tier, allowing it to outspeed base 110's, including mega diancie, mega gallade, latios, latias and gengar. Its one of the most reliable keldeo checks in the tier, pivoting in and being able to easily kill keldeo with psyshock. Bulky can reflect type important stuff like bisharp, making it an excellent glue on teams that need something that can check a variety of pokemon. Offensive sets make for excellent cleaners, and it has coverage to easily deal with common switchins. Starmie also has two excellent ability, anaytic making a pain to switch into, while natural cure means it can make for a decent status absorber. Lets not forget the most notable thing about starmie, rapid spin. Starmie is the easily the most reliable spinner in the tier, as excadrill is often to slow to spin unless in the sand, which starmie outspeeds 85% of the tier already and requires no support what so ever. I feel like starmie is an incredibly effective pokemon right now and it should be A+.
Self explanatory.
up to B-
I'm keep the next two short, because I'm pressed for time. Tyrantrum is an extremely powerful wall breaker, that with a choice band equipped, can two-hit KO pretty much everything in the tier with the appropriate move. It also has access to rock polish and dragon dance to boost its subpar speed stat, but its typing and severely lack of bulk on the special side leave it with few opportunities to set up, making no higher then B-.
up to C+
Excellent revenge killer, very deadly against offensive teams, decent cleaner. I don't have to much experience using it, but when I have used it its always got the job done, and I've seen it been used well by other players.
Anyway, on to the innovative stuff. I've got to warn you now, some of these nominations are pretty weird, so I encourage you to keep an open mind and be flexible.
up to B+
I originally nominated this for B, but I personally can see it more on the level of offensive threats such as mega swampert and terrakion, rather then serperior and omaster. Hydreigon is very prediction oriented, which means every time it has an opportunity to attack, theirs a decent chance something will end up dying. Hydreigon is easily able to dismantle most balance cores pretty easily with its stabs alone. It should also be noted that hydreigon actually hits harder then latios, since in can afford to run modest, something latios is incapable of doing. Hydreigon is also extremely versatile offensively. It has literally the best offence movepool in Ou, as well as great mixed attacking stats to achieve this. Hydreigon can even run utility moves such as taunt and tailwind to shut down walls and boost its subpar speed stat respectively. Overall, Hydreigon is extremely threatening to balance builds, has pretty cool typing offensively and defensively and is one of the most powerful wall breakers in the tier, and its ranking should reflect that.
up to A
Okay, I'll probally get a lot of hate for this, but seriously, this thing is just SO (take note on the capitalized so) good right now. I know being weak to talonflames brave bird is big pain in the ... abdomen, but Keldeo is S rank, and its weak to brave bird. What i really think the biggest counter argument (their will definitely be one) to this would be its crippling weakness to stealth rock, so Volcarona will often require excessive team support to be effective, but with excellent partners such as mega diancie and mega sableye introduced, both highly discouraging the use of stealth rock, volcarona will often be able to achieve a quiver dance or two (though I've personally been able to set up many more times on a regular basis) and proceed to sweep the opponents team. Volcarona's typing also provides it with handy resistances to fairy and ice, allowing to set up on sableye and clefable, as well as preventing mamoswine and weavile from revenge killing it. Volcarona is overall a devastating pokemon when provided the correct support, and I feel it should move to A.
up to A
This is extremely underrated mega. Mega alakazam is armed to the spoons with fantastic special attack and speed, backed up a versatile and deadly ability, and a wide offensive movepool. Mega Alakazam is one of the best pokemon in the current meta when it comes to revenge killing a cleaning. Combination of psychic, focus blast and shadow ball provides perfect neutral coverage, giving alakazam a versatile 4th moveslot. However, one of the deadliest aspects of mega alakazam is its ability: Trace. This allows alakazam to copy the ability of the opposing pokemon. However, due to mega alakazams excellent speed tier, it will often be sent into revenge kill something such as landorus, and trace sheer force. Or trace swift swim to stop a sweep. Trace flash fire to wall heatran. Trace technician to turn hp fire into the new flamethrower. Alakazam will often end games do its high speed tier, as well as excellent special attack stat. Combined with a deadly ability, an excellent movepool, and excellent speed, mega alakazam is arguably on the deadliest revenge killers and cleaners in the current metagame.
